...... above is a municipal boundary post, which (I believe) originally marked the limit of Belfast electoral constituencies. Of course constituency boundaries have changed radically since these posts were first erected but, for some reason, they have been left in position.
The inscription reads:
Victoria, a division of Belfast, was a UK parliamentary constituency in Ireland. It returned one Member of Parliament (MP) to the British House of Commons 1918-1922. This constituency comprised the north-eastern half of East Belfast, based on the then Victoria ward of Belfast City Council. Prior to the United Kingdom general election, 1918 and after the dissolution of Parliament in 1922 the area was part of the Belfast East constituency. wikipedia
A photo of a boundary post, in much better condition, for Cromac Ward can be seen here.
This Royal Mail box is interesting because the insignia on the front 'GR' shows that it was erected during the reign of George VI (11 December 1936 – 6 February 1952) and at 50+ years it is still going strong. I believe there may still be at least 1 mail box with the 'VR' insignia in existence in Belfast and if I come across it I will be sure to take a photo.